1. Field of Use
The present invention is related to a compact, highly portable, user-friendly sleep disorder diagnosis and screening device. The present invention is further related to a respiratory belt to monitor certain parameters of a subject's respiration while at the same time serving to position and mechanically stabilize a compact data acquisition unit about a subject's thorax or abdomen. In one preferred embodiment, the invention comprises a respiratory belt which is placed circumferentially about a subject's thorax or abdomen and to which a compact data acquisition unit capable of recording and/or monitoring at least airflow, respiratory effort and blood oxygen saturation is attached. During use, the respiratory belt is worn by the subject while the subject sleeps and a compact data acquisition unit is attached to the respiratory belt, to which appropriate additional sensors and components such as a pulse oximeter and a nasal cannula are connected. Data is then collected using the device while the subject sleeps and is subsequently used to determine whether the subject has, or is at risk of having, a sleep disorder.
2. Technology Review
Nearly one in seven people in the United States suffer from some type of chronic sleep disorder, and only 50% of people are estimated to get the recommended seven to eight hours of sleep each night. It is further estimated that the medical and social costs associated with sleep deprivation (loss of productivity, industrial accidents, etc.) exceed $150 billion per year. Excessive sleepiness can deteriorate quality of life and is a major cause of morbidity and mortality due to its role in industrial and transportation accidents. Sleepiness further has undesirable effects on motor vehicle operation, employment, higher earning and job promotion opportunities, education, recreation, and personal life.
Primary sleep disorders affect approximately 50 million Americans of all ages and include narcolepsy, restless legs/periodic leg movement, insomnia, and most commonly, obstructive sleep apnea (OSA). OSA's prevalence in society is comparable with diabetes, asthma, and the lifetime risk of colon cancer. OSA is grossly under-diagnosed, with an estimated 80-90% of persons afflicted having not received a clinical diagnosis.
Sleep disorders are currently diagnosed using either simple, subjective methods, various sensor-based objective methods or a combination of the two.
Subjective methods, such as the Epworth and Stanford Sleepiness Scales, generally involve questionnaires that require subjects to answer a series of qualitative questions regarding their sleepiness during various times of the day or while performing various daily activities. With subjective methods such as these, however, it is found that patients usually underestimate their level of sleepiness or they deliberately falsify their responses because of their concern regarding punitive action or as an effort to obtain restricted stimulant medication.
Objective methods of diagnosing sleep disorders generally use a combination of sensors and various physiological measurements to examine a subject's sleep health. One example of such an approach is the use of all-night polysomnography (PSG) to evaluate a subject's sleep architecture. Sleep testing in this manner typically requires measurement of many parameters including brain electrical activity, eye movement, skeletal muscle activity, heart rate, heart rhythm, breathing rate and breathing effort, and blood oxygenation among others. Because of the many sensors used in this approach and the overall complexity of PSG, these tests are typically conducted in a sleep laboratory. While the use of a sleep laboratory and measurement of the many parameters listed above can be advantageous in certain regards, this approach is not without significant drawbacks. Among the difficulties that accompany sleep testing in a sleep laboratory is the fact that a sleep laboratory cannot provide information about a subject's regular sleeping environment. Further, because of the unfamiliar sleeping quarters, the stress of travel to a sleep laboratory, or various other anxieties, many subjects experience “first night effect” when undergoing sleep testing in a sleep laboratory and are unable to properly sleep during testing. Because of this, the first night effect often requires a second night in the sleep laboratory to obtain accurate results for a subject's sleep test leading to greater expense for all parties involved and greater inconvenience to the subject being tested. Additionally, many subjects simply do not need measurement of the numerous parameters typically examined using PSG in a sleep laboratory in order to be effectively tested or diagnosed for a sleep disorder.
In addition, one important parameter to monitor during sleep disorder screening or diagnosis is a subject's respiration. One common method of monitoring a subject's respiratory effort and/or respiration volume is the use of a respiratory belt. Currently, respiratory belts are used only as sensors and, as such, are generally connected to an electronic device via significant lengths of wire which cause signal degradation and can interfere with subject mobility and/or comfort. This method of connection is necessary because current sleep diagnostic and screening devices are too large to be conveniently connected directly to the respiratory belt and/or current respiratory belts are not designed to perform the task of mechanically supporting or stabilizing a data acquisition system.
To address these shortcomings, a variety of sleep testing systems have been developed. However, many of these have been of limited portability, difficult for an untrained user to effectively utilize, and limited in their ability to record data.
It is therefore an object of the present invention to provide a compact, highly portable, user-friendly sleep disorder diagnosis and screening device. It is still another object of the present invention to provide a respiratory belt capable not only of serving as a respiratory sensor, but also of mechanically supporting and effectively securing a sleep data acquisition unit to a subject during sleep testing, allowing for greater mobility and comfort to the subject and also providing greater overall portability of the sleep diagnosis and screening system. It is still another object of the present invention to provide a compact, highly portable, user-friendly sleep disorder diagnosis and screening device which can effectively screen for/diagnose the presence of sleep apnea in a subject.